Peculiarities of pharmacokinetics in young animals

In young animals, especially in newborns, absorption, distribution, metabolism and elimination of drugs differ markedly from adults. Respective differences and the cause of these differences are described, including some examples of drug pharmacokinetics in young and adult animals of different species. However, the estimation of pharmacokinetic differences and their pharmacological consequences in young animals is not generally possible, because published data on characteristics of pharmacokinetics in young animals are available only for relatively few drugs. Furthermore, such estimation is complicated by an interaction of different pharmacokinetic processes. Thus, a generally accepted adaptation of dosage schedules for drugs in young animals cannot be offered as yet. In any event, veterinarians should consider the age-dependency of drug pharmacokinetics when drugs, dosages and dosage intervals for treatment of young animals are chosen.